• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

Backfiring when throttle is backed off

  • Thread starter Thread starter Anonymous
  • Start date Start date
A

Anonymous

Guest
Well the title says it, i am now riding my bike on a regular basis and i put new plugs in , gave it a oil change with mobile 1 fully synthetic and new filter. I synced the carbs the best i could but have the equipment to do it again. I also rebuilt them and now i turned my air mixture screws out to 3 turns because 2 were not doing anything. The question i got is What causes backfiring when the throttle is backed off after reving and why does my bike not get great gas mileage is it because its a 1100 cc. What do i need to do to fix the backfiring. Thanks for your help.
 
100 cc bikes usually get excellenyt gas mileage-over 40 at least. Again--What color are your plugs burning now??
 
Back firing

Back firing

Back-firing = lean, checked for ill fitting inlet (Front & back of carbs)rubbers as you have removed the carbs. Remove plugs and check same color on all four plugs.
 
It is also possible that it is running so rich that it is in fact raw fuel igniting in the pipes. What colour are your plugs?
Dink
 
I will pull my plugs monday when i have off work or sunday which ever is possible, how do i put a picture of them on this site so you guys can see what they look like?
 
Normally,when you adjust the side air-screws out more,the backfiring will increase. It is a lean condition. Try about 1 1/2 turns out and re-set idle.
 
also a leaking exhaust gasket at header pipe will backfire when throttle is closed, and,a too lean a pilot air jet will do it
 
Did you fix this problem ?

My 850 has started doing the same thing.
 
Madoc,

I also have this with my 850, the reason for it being (in my case) the actual muffler....where it is clamped into the pre-muffler (crossover) has with time, pulled itself out far enough to where the "notched gaps" are showing. This allows the cold air to be sucked into the exhaust, creating the backfires.....especially when letting off of throttle.

You can undo the clamp....and push muffler further into the assembly and reclamp tight...but with time it just wants to "slide out about 1/2 inch and expose those gaps again.
 
Back
Top